Methods of well completion or workover of fluid containing subsurface formations

ABSTRACT

The invention relates to well completion or workover of fluid containing subsurface formations by packing off that portion of the well bore adjacent the fluid containing formation from the well bore above this formation and thereafter creating a low pressure void in the packed off portion so as to cause a surge of fluid from the formation into the created low pressure void. This low pressure void impressed upon the fluid containing subsurface formation may be utilized as a source of seismic energy for delineating the type of fluid or formation existing in the subsurface formations adjacent to or surrounding the well bore.

United States Patent 1 1 1111 3,923,099

Brandon 1 1 Dec. 2, 1975 1 1 METHODS OF WELL COMPLETION OR 156] References Cited WORKOVER OF FLUID CONTAINING UNITED STATES PATENTS SUBSURFACE FORMATIONS 2,361.558 10/1944 Mason 166/299 [75] Inventor: Clarence W. Brandon, Nashville, 295,122 12/1959 -F 66/249 Tum 3,189,092 6 1965 BOdlnC 166/249 3,240,273 3/1966 Solari ct a1 166/299 [73] Assignee: Orpha B. Brandon, Nashville, Tenn.

; a part interest Primary Exuminer-Stephen J. Novosad 22 F'led: Mar. 27, 1975 l l 1571 ABSTRACT [21 1 Appl The invention relates to well completion or workover R l t d U5, A fi i D t of fluid containing subsurface formations by packing [63] Continuation-impart of Ser. No. 355.239, April 30, Off 9? porno f bore adjacent the flulfi 1973, abandoned, which is a continuation of Ser. No. Contammg formatmn tmm the bore abOVc thls 557173, J 13 19 abandoned which is a formation and thereafter creating a low pressure void continuation-in-part of Ser. Nos. 853,405. Novv 16, in the packed off portion so as to cause a surge of 1959 Pat. No. 3,255,820, and Ser. No 665,995, fluid from the formation into the created low pressure 19557, 3 1 which i5 8 void. This low pressure void impressed upon the fluid containing subsurface formation may be utilized as a and source of seismic energy for delineating the type of Aug. 31, 1951, Pat. No. 2,796,129.

flu1d or formation existmg 1n the subsurface forma- 1521 11s. c1. 166/249; 166/250; 166/286; ions djacem Surrounding the 166/307; 166/308; 166/281 [51] Int. Cl. ..E2lB 33/13; E21B 43/26;

E21B 43/27 39 Claims, 15 Drawing Figures [58] Field of Search 166/249, 250, 307, 308,

US. Patent Dec. 2, 1975 Sheet 1 of6 3,923,099

US. Patent Dec.2,1975 sheath 3,923,099

llO I06 U.S. Patent Dec. 2, 1975 Sheet 3 of6 3,923,099

US. Patent Dec. 2, 1975 Sheet 4 of6 3,923,099-

O O 6 M 8 O 7///A /////////r//////////////// 07////// A? I m r F 4 ll 10) I 6 0 M w 8 US. Patent Dec. 2, 1975 Sheet 5 of6 3,923,099

1 h w. h.w-

US. Patent Dec. 2, 1975 Sheet 6 of6 3,923,099

METHODS OF WELL COMPLETION OR WORKOVER OF FLUID CONTAINING SUBSURFACE FORMATIONS CROSS-REFERENCES TO RELATED APPLICATIONS This is a continuation-in-part of application Ser. No, 355,239 filed Apr. 30, 197 3, now abandoned, which is a continuation of Ser. No. 557,273 filed June 13, 1966, now abandoned, whichis a continuation-in-part of application Ser. No. 853,405 filed Nov. 16, 1959, now US. Pat. No. 3,255,820, and application Ser. No. 665,995 filed June 17, 1957, now US. Pat. No. 3,302,720, which in turn is a continuation-in-part of application Ser. No. 296,038 filed June 27, 1952, now US. Pat. No. 2,866,509, and application Ser. No. 241,647 filed Aug. 13, 1951, now US. Pat. No. 2,796,129.

BACKGROUND OF THE INVENTION Broadly this invention discloses methods of use of created low pressure voids or zones of rarefaction within well bores at locations adjacent to fluid containing subsurface formations and wherein these created voids within the well bores causes a rarefied surge of fluids and other matter from the subsurface formations into the created voids within the well bores.

These low pressure voids impressed upon the fluids of the subsurface formations, which may be oil, gas, water or other types or mixtures of fluids, may become sources of seismic energy for delineation of various types of subsurface fluids or formation structures existing adjacent to or in the area surrounding the well bores in which the voids are created.

For the sake of clarification of the hereinafter disclosures relating to this invention, the creation of the low pressure voids or the zones of rarefaction and the substantially instantaneous primary negative pulse or surge of fluid thereinto is termed an implosion and the positive pulse or reactive surge of fluid outward therefrom is termed an implosive reaction.

An implosive effect, as distinguished from an explosive effect, is generally created by the primary immediate inrush of a high pressure fluid into a created zone of low pressure.

This invention relates to methods and apparatus for creating implosions and implosive reactions. More particularly, this invention relates to apparatus for creating implosions and implosive reactions within a relatively confined space having fluids under pressure. Still more particularly, this invention relates to apparatus and methods useful in treating subsurface formations.

This invention also relates to the use of implosions and implosive reactions as an augmenting or modulating method and means for sonic waves which are from a source either in the form of single pulses in any timed or irregular fashion or with periodic pulses being created or maintained in fluids.

This invention also is inclusive of method and means of transference of sonic or energy carrying waves across boundaries of various pressures and types of fluids within confined areas of fluids and particularly so in the treatment of subsurface formations. The problem of creating an implosive reaction resides first is establishing a zone or space of low pressure within the confines ofa high pressure fluid. In some instances the high pressure is caused by hydrostatic pressures or in other instances by mechanically created pressure such as with pumps, compressors, etc. Secondly, the problem is one of establishing instantaneous communication or collapse between the low pressure space and high pressure fluids. The enormity of the implosive reaction and its resultant pulses will vary according to the differential pressure established between the low and high pressure spaces, the volume of the low pressure space, and upon the instantaneous communication between the two spaces.

Typically, the implosive reaction caused by the instantaneous communication of high pressure and low pressure zones creates an initial negative or rarefaction wave impulse instead of a positive pulse as is created from an explosive reaction. Immediately following the rarefaction wave pulse is the opposite reactive, compression or positive high pressure pulse. In some instances this latter pulse energy is greater than the former. As used and defined herein the term implosive or implosion reaction pulses is defined to include both the initial rarefaction pulse and positive or compression pulse and those pulses resulting thereafter.

The above information relative to implosions and implosive reactions was substantiated by instrumentation and results by the use of the apparatus shown in detail in my earlier filed applications parent hereto, wherein the so-called cavitation valve, detailed in originally filed FIGURES therein herebefore is controllably operated as to timed periods of operation in the creating of and/or modulating of sonic waves. It was found that a substantially instantaneous collapse of high pressured fluid into a created low pressure zone within the confines of the high pressured fluid could be achieved by proper operating control of this so-called cavitation valve, and that the substantially instantaneous collapse of the high pressure into the void caused an implosive effect that was followed thereafter with a very severe impactual shock wave or an implosive reaction pulse. It was the results of these findings and the knowledge that this cavitation or implosive wave generator could be placed down within the well bore, next to the productive formation if desired, that resulted in the filing of my parental application Ser. No. 853,405 on Nov. 16, 1959, now US. Pat. No. 3,255,820.

In the art of drilling and producing subsurface formations containing typically oil, gas or water, or combinations of these, it becomes necessary from time to time to workover and/or completely clean out the well formation to more efficient production therefrom. Well known completion techniques such as hydraulic fracturing, acidizing and perforating have heretofore been taught and used by others. However, these completion and workover methods and apparatus typically involve the use of what might be broadly termed an explosive or positive pressure characteristic for their usefulness. In some instances it has been found that this prevents the immediate removal of debris, mud-cake, sand and the like from the plugged pores of the subsurface formation and usually tends to wedge them deeper into the formation.

In the normal production or swabbing of fluids from subsurface formations by the continuous withdrawal of a packer it appears that the low pressure area produced below the pump or swab brings debris, sand or cement materials into narrowed portions of the well causing plugged or decreased fluid permeability.

In some instances where a swab operation has been used alone in wells increased production has occurred by the mixing of higher molecular weight hydrocarbons into the lighter produced crude aiding flow through previously blocked channels or pores. In other instances, however, the swabbing disturbs these heavier ends without solvent or blending action with the lighter ends, forcing them to the well and decreasing permeability.

In many wells the gas produced around the subsur face formation will come out of solution with the oil causing a reduction in temperature of the produced fluids which in turn causes the heavy end hydrocarbons of the produced fluids to deposit or settle out within the immediate area of the formation causing plugging and reduced permeability.

Accordingly, it becomes an important feature of this invention to provide methods and apparatus for use of implosive reactions which overcome the .objections to methods and apparatus heretofore taught and used.

In the methods and apparatus disclosed in my parental application Ser. No. 665,995, filed June 17, 1957,

now U.S. Pat. No. 3,302,720, it was found that this heretofore noted cavitation or implosion valve worked very satisfactorily at the surface in its initiating of cavitational or implosive reactions and in its augmentation or modulation of other sonic or energy carrying waves. Especially was this so where the subsurface formations had sufficient reservoir pressure or where the permeability was of small enough value so that the well bore could be pressured up with but small fluid loss into the interstices of the formation.

However, it was found that many productive formations would not sustain a column of pressured fluid without pumping in great amounts of unwanted fluids which will contaminate and lower the productive capacity of the formation or which will require a good deal of time for the fluids to be displaced from the interstices of the formation. Therefore, where it became desirable to controllably select the intensity or energy of pressure wave output from implosive reactions and- /or modulated sonic waves, as by increasing the pressure of the fluid in which the pressure waves are being created, this method and means was provided whereby limited amounts of fluids are allowed to go into the formation whereby the well bore at the surface could be controllably pressured, yet permitting sonic or energy carrying waves created at the surface to have their en ergy content transferred into and out of the formation with substantially no loss except that which is helpful in increasing production from the formation. Such a method and means is provided as an object of this invention wherein apparatus as described is placed at selected locations in well bores, preferably adjacent a productive formation, and by controllable back pressure (and/or variance of exposed areas) between that of a high pressure hydrostatic column of fluid in the well bore and a lower pressure of fluid existing in the productive formation, a limited amount of fluid is shoved or injected back into the formation.

Besides the advantages of the method and means of this invention described above,.when used in conjunction with the method and apparatus detailed and taught in my parental applications Ser. No. 241,647 filed Aug. 13, 1951, now U.S. Pat. No. 2,796,129, Ser. No. 296,038 filed June 27, 1952, now U.S. Pat. No. 2,866,509, and Ser. No. 665,995 filed June 17, 1957, now U.S. Pat. No. 3,302,720, there are other advantages and objects such as provision for method and means to introduce gases, preferably liquefied, into productive formations without interference to the transfer of sonic or pressure wave energy in the well bore by the gas becoming vaporized, as during rarefactions of the sonic waves or of the inplosions.

OBJECTS OF THE INVENTION One object of this invention is to provide methods and apparatus for general industrial or well use of an implosive action or reaction by the collapse of high pressure fluids under pressure into a zone or space of low pressure and further to provide means for regulating said action or reaction by variations in volume between the two zones (i.e. vary either the high or low pressure volume), the resulting differential pressure and the speed of communication between the two zones.

Another important feature and object of this invention is to provide methods and apparatus for creating implosive reactions and to provide means for utilizing the resultant energy from such reactions.

Another object of this invention is to provide a method and apparatus for treating subsurface formations and fluids for increased production therefrom by the creation of an implosive reaction within the producing formations in situ, or within the well adjacent the formation.

A further object of this invention is to provide methods and apparatus for increasing production of fluids from subsurface formations and maintain solid material in suspension during swabbing or creation of a zone of low pressure below an upward moving piston device by simultaneously creating one or periodic implosive reac tion pulses of predetermined amplitude and phase relationship, the motivating force for such reactions caused by the upward pull of said piston or swab.

Another object inclusive of the above object is to provide methods and apparatus for causing intense single or periodic pressure peaks following, equal to or greater than the pressure change of each negative implosive reaction pulse.

Another object of this invention is to provide implosive wave pulse forms having predetermined and controllable characteristics for application to subsurface formations.

Another object of this invention is to provide methods and apparatus for producing and lifting fluids from subsurface formations to the surface by implosive reaction pulses created within the well, said pulses continuing upward for maximum lift and/or radiated downward in a short periodic manner.

Another object of this invention is to provide apparatus for creating implosive and resultant impulses which is removably anchored in a well adjacent a subsurface formation, said impulses created by pressure fluid movement through the apparatus.

A further object of this invention is to provide methods and apparatus which is releasable under extensive hydrostatic fluid pressure within a well and further provide apparatus which is operable only under predetermined hydrostatic pressure loads to create implosive reactions.

A still further object of this invention is to provide method and apparatus for creating and utilizing implosive reactions and resultant pulses to rupture and fracture subsurface formations. An additional object of this invention is to provide methods and apparatus in accordance with the above which simultaneously maintains emulsification of fracturing liquids and/or suspension of bridging and propping agents such as sand, etc., by the implosive reaction pulse or pulses.

A still further object of this invention is to provide methods and apparatus for creating implosive reaction impulses in combination with a reciprocating cable tool drilling rig which causes said impulses to not only assist said drilling but also lift fluids from the well.

A still further object of this invention is to provide apparatus adaptable to reciprocating type pumping equipment used in producing wells whereby implosive reaction pulses are created in combination with said reciprocation.

An additional object in accordance therewith is to provide a unitary pumping structure for wells which eliminates standing valves at the lower end of the production tubing and for creating kinetic energy from an implosive reaction to assist in pumping fluids from the formation. Additional methods and apparatus include selective and continuous fracturing of the subsurface producing formation by the combined pump and implosive reaction generator. A further object includes means for preselecting the intensity of the resultant implosive reaction prior to insertion within a well which is based on predetermined hydrostatic or mechanical pressure.

A yet further object of this invention is to provide apparatus which may be readily inserted and withdrawn from a well with appropriate bypass, safety and release mechanisms to prevent sticking and overloading by fluid columns in the well.

A still further object of this invention is to provide apparatus and method for creating implosive and resultant reactions of a desired pulse form and to further provide means for changing said pulse form as to intensity and frequency readily and simply by an operator at the surface such as by placement of the apparatus at preselected distances from the formation or device treated.

An even further object of this invention is to provide apparatus and method of creating implosive and resultant reaction pulses useful in secondary and tertiary recovery of oil from subsurface formations.

Still another object of this invention is to provide method and apparatus for treatment of subsurface formations with implosive and its resultant reaction pulses while simultaneously or in combination with well known well workover and completion techniques such as hydraulic fracturing, acidizing, perforating, and cementing, etc.

A further object in accordance therewith is to provide methods and apparatus for injection of treating fluids such as fracturing fluids, solvents, acids, etc., simultaneous with the aforesaid implosive reaction pulse or timed for introduction at predetermined phase angle of the initial pulse or resultant pulses.

Another object of this invention is to provide methods and apparatus for creating implosive reactions wherein the causative force for actuation of said apparatus occurs by fluid velocity or quantity of flow or pressure or by separate and distinct sonic wave generators.

Yet another very important object is to provide method and apparatus whereby sonic wave generators at the surface may have their sonic wave output, whether in the form of single pulses in any timed or irregular fashion or in the form of periodic sonic pulses capable of creating and maintaining sonic standing waves in the well bore and/or into the formation, augmented or modulated adjacent the formation for cor:- trollable effects upon, into and through productive formations.

Another important object in connection with the last above object is to use the means adjacent the formation as a controllable method and apparatus for allowing but limited entry of pressured fluid that is in the well bore into the formation while allowing transfer of sonic wave energy from the surface down the well bore and into and out of the formation.

A further object is to provide method and means whereby liquefiable gas may be introduced into and taken from productive formations without interference to sonic wave energy being transported in well bores.

Another very important object is to provide method and apparatus whereby sonic and energy carrying waves may be transformed and transferred across various pressure boundaries with substantially no attentuation of wave energy. I

A further object is to provide methods and apparatus for producing implosive reactions simultaneously or in various phase relationships in two or more wells connecting with the same subsurface formation during swabbing, producing, treating or secondary recovery of the fluids from said well or wellsf A still further object of this invention is to provide methods and apparatus for creating implosive reactions in combination with subsurface reservoir testing means, said combination being of unitized construction to include other well known subsurface formation treating processes, solutions, and apparatus controlled at the surface in a step by step operation or in automatic timed sequence. In accordance therewith, it is an even further object of this invention to provide a unitized apparatus for perforating a formation or casing, fracturing said formation with an implosive pulse, treating the formation with treating fluids, testing the amount of formation reservoir energy and sequentially plugging same permanently or temporarily, if necessary.

An even further object of this invention is to provide apparatus useful particularly in wells for creating heat energy by producing an implosive reaction in or adjacent the well and by the means of the implosive reaction to transfer sensible heat from the well to a distance in the formation.

A still further object is to provide apparatus for creating implosive reaction pulse or pulses capable of operation in wells from a wire line, tubing, sucker rods, drill pipe and the like.

Another important object is to permit the use of treating fluids in a producing formation by the use of the implosive reaction wherein the means of causing the reaction and the treating fluids are isolated from fluids of the well bore and are lowered into place in the well bore on a wire line or pump rods. Yet another object in conjunction with the last above object is to use the pressure of the fluids within the well bore as an assisting means in causing the treating fluids to go into the producing formation. A further object in conjunction with the last two objects is to provide means so that fluids from the well bore may follow the treating fluids into the producing formation.

These and other objects will become more apparent upon further reading of the description, operation and claims of this invention when taken in conjunction with the following drawings of which:

FIG. 1 is an elevational view partly in section of apparatus constructed in accordance with this invention as suspended in operational position within a well on a wire line cable.

FIG. 2 is an additional diagrammatic illustration of the apparatus of FIG. 1 suspended within the well on a tubular attachment conduit.

FIG. 3 is a top continuation of the apparatus according to FIG. 4 and represents an enlarged elevational view partially in cross-section of apparatus for attachment to surface operational wireline, sucker rods, tubing or other apparatus, not shown.

FIG. 4 is a detailed front elevational view, partially in cross-section, of an implosive pulse generating apparatus useful in wells according to this invention.

FIG. 5 is a partial cross-sectional view of additional attachment apparatus for the apparatus of FIG. 4 useful according to another embodiment of this invention.

FIG. 6 represents a back-off or safety attachment device to the apparatus of FIG. 4 which is useful in a further embodiment according to this invention.

FIGS. 7, 8 and 9 are views of an implosive reaction method and apparatus constructed according to an embodiment of this invention.

FIG. 10 is an elevational view, partly in section, of the apparatus of this invention in combination with well completion or workover tools in accordance with an additional embodiment and method of this invention.

FIG. 11 is an upper continuation of the apparatus and methods described in FIG. 10.

FIG. 12 is a sectional view taken along the line 1212 of FIG. 4.

FIG. 13 is a front elevational view partially in crosssection of a wireline operated embodiment for use in various well treating procedures using the implosive pulse generator according to this invention.

FIGS. 14 and 15 are cross-sectional views taken along the lines 14-14 and 1515, respectively, of FIG. 13.

DESCRIPTION Referring now to FIGS. 1 and 2, the apparatus of this invention is described in relation to use within a relatively smooth bore well casing 10. In the view of FIG. 1 connector 12 is for attachment to well known and used wirelines socket tools 13 or sucker rods (not shown) for movement, placement and operation of the apparatus of this invention in casing 10. The attachment 12 is more clearly illustrated in FIG. 3. For attachment to tubing 11, or hollow sucker rods, connector 12A is used. This is likewise described in FIG. 5 in greater detail. Numeral 14 (see FIG. 1) designates one or more passageways extending from the fluid filled annulus space 15 into tubular passageway 16, shown more clearly in FIG. 3. Wireline 18 extends from socket 13 to a winch or pulling apparatus at the surface, not shown. Stuffing boxes 20 and 20A are adapted to seal the annular space 16 between wireline 18 and casing 10. Valved connection 22 permits fluid control within space 15. Valved connection 24 (see FIG. 2) permits fluid control to tubing 11. The implosive reaction pulse generator is generally indicated by bracket and extends within the well casing 10 to predetermined positions with respect to a subsurface formation 32 having perforations 34 providing communication with the well.

Referring now to the combined views of FIGS. 3 and 4. implosive reaction pulse generator 30 is described in relation to its use and placement within a well using a wireline or sucker rod, not shown.

A check valve 40 and seat 42 are adapted to regulate fluid flow through passageways l4 and 16. Resilient spring means 44 is adapted to maintain valve 40 in a normal closed position against seat 42 and further regulates the pressure at which valve 40 will be forced open or away from seat 42. Rotation of threads 46, part of attachment or connection 12 and valve seat 42 regulates the tension of spring 44 for control of the operating or opening pressure necessary to force valve 40 away from seat 42, the full operation and function of which will be hereinafter described.

Threaded lock nut 48 retains the spring tension position by movement about threads 46 into engagement with valve housing member 50. Valve 40 is retained in a non-opening position by threaded movement of adapter 12 to a lowermost position. In one embodiment valve 40 is forced in sealing abutment with a portion of the valve housing 50 therebelow by movement of adapter 12. Valve housing 50 threadably interconnects between adapter 12 and the implosive reaction generator 30 with one or more tubular subs 52 for attaining a desired length. The sub includes central bore 54 common throughout the length of the apparatus 30 from valve 40 into communication with the fluid in the lower portion of the well.

An inner mandrel 56 is threadably coupled to tubular sub 52 or in some instances directly to valve housing 50 and extends for the length of implosive pulse generator 30. An outer mandrel 58 is threadably connected to inner mandrel 56 at its upper end. The outer mandrel is adapted to receive unidirectional packing 60 such as the well known cup type packers as used in well servicing techniques and completions. The packer is adapted in one embodiment to be slidably received about mandrel 58 between an upper stop 62 and a lower stop 64. In the lower position shown, the packer is sealed to prevent fluid movement in the annular space 15 from above to below. The bottom portion of the packer, under fluid pressure above, tends to seal against stop 64. A splined or beveled portion 66 is provided adjacent packer 60 as shown such that when the packer is moved upward relative to mandrel 58, as occurs during lowering within the well, fluids will bypass from below to above. In the event an overloaded condition occurs during upward movement of the apparatus, or it becomes undesirable to swab the fluids above packer 60, a shear release mechanism can be incorporated between the packer and mandrel 58 to permit bypass of fluids. Bypass can likewise occur by opening of valve 40 permitting fluid flow across generator 30.

Passageway 67 extends from above bypass splines portion 66 and packer 60 providing communication from the annulus space 15 into main cylinder space 68 formed between outer mandrel 58 and inner tubular mandrel 56. A cylindrical piston 70 is sealed between the inner and outer mandrels using O-ring type seals 72. The piston includes a connected sleeve portion 74 adapted for reciprocation therewith. Movement of the piston and sleeve is regulated as desired by spring which normally tends to force sleeve 74 and piston 70 upward. A retaining sleeve 82 about mandrel 56 is engaged with retaining nut 84 threaded along the inner mandrel at the lower end to adjust tension of spring 80. Threaded lock nut 86 is provided for maintaining such a setting.v

Slidably received about piston sleeve 74 between it and the outer mandrel portion 58 is assembly sleeve 88 which, as seen in cross-section, comprises an upper sleeve portion 90 sealed with respect to the sleeve 74 by O-ring packing means 92. A splined or slotted portion 94 exists longitudinally of assembly 88 to permit bypass of fluids in the annular space across unidirectional packer 96. Packer 96 extends in an operational direction opposite that of upper packer 60. This packer is in all respects similar to the packer 60 in its unidirectional operation and design, i.e., allows movement of fluids in one direction and prevents flow in the other direction when so positioned during operation. The cylindrical assembly 88 is normally in the position as shown permitting bypass of fluids within the annulus space across packer 96 through slots 94 by the tension of resilient spring means 98 acting between lower sleeve 100 and retaining nut 102 which is threaded about inner mandrel 56 and held by lock nut 104. One or more spring loaded latching devices 106, one of which is shown in cross-section, is provided about the periphery of assembly 88 to cause engagement with sleeve 74. Latch 106 is movable about a shaft 108 maintained by spring means 110 abutting against cylindrical assembly 88, in engagement through a lip 112 into a recessed portion 114 of piston sleeve 74, the operational movement of which will be hereinafter described.

Latch member 106 is adapted, upon rotation about shaft 108 against the tension spring 110, to be disengaged from recess 114 by striking release cylinder 116 which is threadably adjusted to a sleeve 118 formed as a part of nut 84. A lock nut 120 prevents movement of the cylinder 116. The lower outside threaded portion of the inner mandrel 56 is adaptable to be attached with other well servicing and drilling equipment, such as perforators, well pumps, etc.

Referring now to the embodiments described in FIG. 5, the apparatus is similar to that described in FIG. 3 in that it describes a top continuation attachment for the implosive reaction pulse generator mechanism 30.

The device has primary utility for attachment to tubing, drill pipe, hollow sucker rods and the like using adapter 12A forming passageway 16A. The passageway terminates with a rupture seal disc 130 formed as a part of valve 40A. The go-devil device 132 illustrated is designed for operation with the device of FIG. to rupture disc 130 and includes a body portion 134 and guide vanes 136.

Referring now to the safety back-off device 138 of FIG. 6, the apparatus is typically installed between implosive pulse generator 30 and the upper attachment valve housing 50. However, in some instances it is attached above valve housing 50 to adapter 12A. The device includes upper and lower cylindrical members 140 and 142 attached to each other by left-handed threads 144. Bypass openings 146 are sealed from the annulus space by O-ring seal 148. In the instance a release of pressure from space 54 becomes necessary, as for example when removal of generator 30 is desired without swabbing the well and/or creating implosive pulses, right-handed rotation of cylinder 140 with respect to fixed cylinder 142 releases the seal 148 and permits fluid communication from annulus to interior space 54 through openings 146.

Cylinder 140 of the safety back-off device 138, in one embodiment, is rotated sufficiently to allow ports 146 to be opened without being physically parted. This is dependent upon the length of the threads 144 with respect to ports 146. In those instances where the generator and/or parts connected thereto are stuck within the well, member may be physically separated to permit appropriate fishing tools to connect with member 142 and remove the stuck apparatus from the well. The relative rotation in either of the above instances occurs by reason of the anchored generator which is held by pressure or stuck within the well.

FIGS. 7, 8 and 9 are views of an implosive reaction method and apparatus constructed according to an embodiment of this invention. The arrows are indicative of the motion of parts and'pressure fluids.

FIGS. 10 and 11 show an assembly of an alternate embodiment using a bullet or shaped charge perforating device 150 attached at the lower end of implosive pulse generator 30. Tubing 11 connects with tubing 52 above generator 30 through connector 12A, valve housing 50 and safety back-off 138, as described in FIGS. 5 and 6. Tubing 1 1 terminates at the surface with cap 152. Conduit 24 interconnects tubing 11 with various well treating materials schematically shown in containers 154 and 156 and 158, such as acids, fracturing fluids, solvents, plugging materials such as cement, etc., which are appropriately connected with a pump means 160. Block diagram 162 represents an energy source such as a pump, compressor, or sonic wave generator such as tose disclosed in my parental application Ser. No. 665,995 filed June 17, 1957, now US. Pat. No. 3,302,720, which connect with annulus space 15 to provide energy as may be desired to actuate implosive pulse generator 30, as hereinafter described.

Referring now to FIGS. 13, 14 and 15, apparatus is illustrated for operation in connection with the implosive reaction generator 30 when supported within a well on a wireline or pump rods and when it is desired to treat a subsurface formation with increment injection of fluids such as acids, fracturing fluids, solvents, emulsions, sealing or cementing agents, etc. Connector or adapter 200, similar to adapter 12 (in FIGS. 1 and 3) represents the top of the apparatus for attachment to a wireline socket or pump rod coupling, not shown. The adapter is threadably attached to barrel 202 at threads 204. Passageway 206 provides communication between annulus space 15 and space 208. Barrel 202 terminates at lengths up to several hundred feet or more for deep well use to a lower connector 210 at threads 212. Lower threads 214 are usually attached to coupling 12A and valve housing 50 of the device shown in FIG. 5, safety sub 138 and thence generator 30, respectively, somewhat similar to the view of FIG. 1.

Barrel 202 is divided into a multiplicity of separate chambers using one or more piston devices such as 216 and 218. Free piston 216 provides a solid seal separating chamber 208 and chamber 220 using an O-ring seal 222. Free piston device 218 comprises a type of check valve permitting bypass of fluids within chamber 220 to lower chamber 224, optional heating chamber 226 and thence space 227 above valve housing 50. The valved piston 218 includes a solid valve seat 228 threaded at the lower end 230 for sleeve 232 which holds perforated retaining ring 234 and spring 236 acting against piston 238 sealed against valve seat 228 and against barrel 202 with O-ring seal 240. One or more ports 242 are locatedabout the interior of piston 238, the functional use of which will be hereinafter described.

Chamber 224 terminates with a control orifice 244 which is seen in the cross-section of FIG. 14. The orifice includes a central opening 246 terminating the beveled stop surface 248. At least one opening 250, preferably more, are spaced about the outer portion of orifice 244 and are of such diameter that they intersect with the beveled surface 248. Orifice 246 and openings 250 provide communication with optional heating chamber 226 from chamber 224.

Heating chamber 226 includes a resistor type heating coil 252 such as sold under the trademark CALROD which is connected to insulated electrical connection 254 adaptable for connection and operation with con ductor cable 18, not shown in this view. The electrical connector 254 is attached or clamped to barrel 202 is a manner well known to those skilled in the art.

OPERATION OF IMPLOSIVE PULSE GENERATOR AND/OR SONIC WAVE MODULATOR Although there are numerous methods and processes adaptable to this invention, broadly speaking, such as in industrial usage, the purpose of the apparatus described heretofore is the creation and usage of an implosive pulse and resultant pulses within high pressure fluids which is specifically adaptable to all phases of oil well seismic exploration, drilling, completion, workover and production or as an augmenting or modulating means to sonic or energy carrying waves used in various methods or processes thereto.

The implosive operation comprises two or more fundamental steps: l the creation of at least two separate fluid volumes having differential pressure therebe tween, and (2) the instantaneous collapse or communication between such volumes and a resultant following high pressure pulse, and (3) if actuated by sonic or energy carrying pulse or waves steps (1) and (2) become a modulating means and method for the particular phase angle to which they are applied to the sonic pulse or waves and/or an intensifier of said sonic pulse or waves.

Referring specifically now to the apparatus illustrated in FIGS. 1, 3 and 4 and FIGS. 7, 8 and 9 which are a preferred mode of carrying out the invention, the numerals used in FIGS. 7, 8 and 9 refer to like numerals in the specific apparatus of FIGS. 3 and 4. Packer 60 is described, however, as a fixed packer for the purpose of simplification. Preferably the apparatus 30 is used in conjunction with a confined bore such as a cased well 10 filled with a fluid supplied through conduit 22 or filled with produced fluid from formation 32.

However, the use of apparatus 30, or other means that will perform like methods of operation, is not confined to use in well bores but may be used generally in industrial methods and processes as well as those uses later described in this application wherein the following detailed description and mode of operation is applicable and wherein casing 10 may be any confining medium or means wherein the methods and processes herein may be performed.

Using connections 12 and 13, valve housing 50 and tubular subs 52, implosive pulse generator 30 is lowered on wireline 18 to a desired position within the well with respect to formation 32. Well fluids are permitted to bypass packers 60 and 96 through splined areas 66 and 94 respectively during the lowering operation. The initial starting position will depend to a great extent upon the treatment desired. For example, it has been found that by locating lower packer 96 at distances from formation 32 equal to multiples of one-quarter of the wave length as predetermined or desired from generator 30 this causes reinforcement of reflected pulses from formation 32 when repetitive or periodic pulses are generated. Reinforcement of the compressive wave pulse following the rarefied implosion reaction pulse occurs through proper placement of valve 40 with respect to the end of mandrel 54 permitting fluid injection during the compression part of the pulse or wave. Even further reinforced energy of the compression wave occurs by injecting heated fluids, such as gases, solvents, light crudes or driving fluids such as water and liquefied petroleum gases. This added energy upon attenuation will drop the energy into reconversion of heat within the formation.

Under certain conditions such as when desired to prevent contamination of well fluids existing above generator 30, valve 40 in housing 50 is adjusted to an inoperative position by movement of connector 12 heretofore described. Using proper length of subs 52 the distance valve 40 extending from the lower end of generator 30 becomes of critical importance in certain operations as hereinafter described.

In the initial starting procedure the pressure across packers 60 and 96 is in equilibrium. Upon the reversal of movement of wire line 18, e.g., upward, bypass slots 66 are closed as packer 60 seals along mandrel 58 and shoulder 64. Accordingly, fluid within the well space 15 is prevented from passing from above to below the packer 60, by fluid pressure expanding same into sealing engagement with tubular casing 10. Further upward movement of mandrels 56 and 58 force pressure fluid such as hydrostatic pressure fluid into bypass 67 and cylinder space 68, forcing piston means 70 and its attached sleeve 74 downward. The amount of pressure necessary to force movement of piston 70 under the action of high pressure fluids is largely determined by the size, type and predetermined tension setting of spring members and 98. Due to interlocking engagement of latch 106 by lip 112 in recessed portion 114, the cylindrical assembly 88 is likewise caused to move downward with the sleeve and piston. Spring 110 associated with latch 106 and assembly 88 maintains this interlocked relationship. Further movement of piston 70 and assembly 88 under the pressure existing in cylinder 68 forces the upper portion 90 of assembly 88 into sealing engagement with the lower packing means 96 thereby shutting off packer bypass channel 94. Further movement thereof causes increased pressure to occur on the lower side of packing element 96 forcing it into sealing engagement with casing 10 similar to that described with packing element 60. Continued movement and withdrawal of mandrels 56 and 58 upward begins the creation of a low pressure space between the two packing members 60 and 96 by the relative movement of the mandrel members and packer 60 upward with respect to downward movement of packer 96 in an opposite direction. This zone of low pressure is sealed from the fluids within the casing. It appears that the resultant force of the implosion is largely a function of the differential pressure across packer 96 and the volume of space between packers 60 and 96. Accordingly, it is possible to arrive at a predetermined intensity of implosive effect by control of operational movement between the packers 60 and 96 and control of the amount of pressure existing about the low pressure zone created. Assembly 88 continues movement downward until latch means 106 strikes release or tripping member 116, providing an instantaneous movement under the action of spring 98 against lower sleeve 100 of assembly 88. Since release member 116 is threadably adjusted upon retaining sleeve 118 the distance and length of movement and hence resultant implosive effect may be readily adjusted or pre-set. The total movement of packers 60 and 96 relative to each other depends upon many characteristics and conditions in addition to the type of workover or completion techniques required. This relative movement may be a matter of a fraction of an inch up to several inches or more.

Although there is some discrepancy as to actually where the implosive reaction pulse is created, it appears that upon the substantially instantaneous release of assembly 88 packer 96 likewise moves into abutment with mandrel 58. This instantaneous packer movement away from the pressure fluid below creates a low pressure void into which the high pressure fluids below instantly communicate to cause the initial rarefaction wave pulse. In other instances, due to changes in spring tension and inertia between assembly 88 and packer 96, there is instantaneous communication in space 94 between the low pressure space between the packers and the relatively high pressure fluid space outside. It is known that an in-rush of fluids establishes the implosive reaction.

Repeated or periodic implosive pulses occur by lowering generator 30 permitting spring tension 80 to return sleeve 74 and piston 70 into engagement with latch 106. Another method consists of alternately releasing the pressure within cylinder 68. A yet further method is the use of a sonic pulse or periodic sonic wave being caused in the fluid within space 15 of casing 10, as for example using the various methods and apparatus referred to in parental application Ser. No. 665,995, filed June 17, 1957, now U.S. Pat. No. 3,302,720, which is a continuation-in-part of prior ap plications Ser. No. 241,647, filed Aug. 13, 1951, now U.S. Pat. No. 2,796,129, and Ser. No. 296,038, filed June 27, 1952, now U.S. Pat. No. 2,866,509. As taught therein these sonic pulses are either single pulses in any timed or irregular fashion or periodic pulses capable of creating and maintaining in the fluid above the implosive pulse generator 30 a sonic standing wave of multiples of a quarter wavelength of the fundamental frequency or one of its various harmonics. In many instances the created implosive and associated pulses release the pressure sufficiently to cause re-engagement with assembly 88.

The generator unit 30 may be activated by periodic upward movement and return of the unit to the original position or by allowing the generator unit 30 to remain in a fixed position from the formation and the bottom of the well in combination with the activation means described in the previous paragraph, that is, by a sonic pulse or by momentarily increasing the pressure of the fluid above the generator 30 or by pressure fluid flowing past and through the unit 30.

In operating the generator unit 30, typically the operator selects the placement at a distance of a quarter wave length that was less than the quarter of a wave length of the fundamental frequency of a sonic wave in the medium being used and hence causes the generator unit to operate at one of the many quarter waves of the harmonics of the fundamental frequency and thus maintain a standing wave condition of sonic waves below unit 30. If the unit is pulled upward continuously. as in a swabbing operation, then the reflected standing wave from the generator unit would be of an increase in wave length going through the various harmonics of the fundamental frequency of wave length in the particular fluid contained in the well. Accordingly, valve 40 would open due to the rarefaction portion of the pulse. The length of the tubing upward actually regulates in time the arrival of the fluid and its joining the fluid below the valve at a phase angle with the pulses from generator unit 30 and the particular quarter wave length of harmonics selected and the resultant position of unit 30 from the bottom of the well. This regulates the distance valve 40 will be above generator unit 30 in order to have the fluid combine with the standing wave impulses at the desired phase angle portion of the standing waves.

Operation in accordance with this invention using tubular apparatus of FIGS. 2, 5 and 6 is substantially the same as using the wireline apparatus described above, i.e., the implosive generator 30 operates in the same manner. The tubular apparatus has particular utility when it is desired to continuously add treating fluids or materials to the subsurface formation below the generator 30 independent of annulus fluids, as more particularly described heretofore and generally under the subheading WELL COMPLETION hereafter.

The implosive reaction occurring from the communication of high and low pressure zones in the fluid about packing members 60 and 96 causes a negative or rarefaction pressure pulse. This pulse is impressed upon the pores of the producing formation through the coupled fluid existing within the well and formation. The fluid exists within the well as produced fluids or is pumped into the well prior to inserting of generator 30. Accordingly the coupling fluid used is an important phase of this invention in well completion and workover. If the apparatus is used primarily as a swabbing tool, the formation fluids will form the coupling medium whereas in other instances oil well acids, solvents, fracturing fluids and drilling fluids are also capable of use with the invention. Following the negative pulse there will be a positive pressure pulse of up to several thousand atmospheres per square inch or higher. Likewise, the high pressure pulse immediately following the rarefaction pulse enters the producing formation with increased beneficial effect for increasing production of fluids therefrom but unlike the rarefied pulse is also propagated upward within the well.

SWABBING WELLS The apparatus is readily adaptable for use as a type of wire line swab for cleaning oil well formations as illustrated in FIG. 1. By a continuous withdrawal of the device up the well an alternating implosive reaction occurs during such travel until the hydrostatic fluid pressure in space 15 is incapable of further movement of piston within the generator.

Where the device is continuously withdrawn up the well valve 40 must be set in an operating condition whereby the upward pull of the device is not sufficient to cause opening of the valve. The valve is caused to be opened, however, when the rarefied wave pulse travels upward in tube space 54 and reaches the underside of valve 40. The differential pressure across valve 40 causes the valve to open, allowing fluid thereabove to be induced down tube 54. This same induction of fluid at valve 40 also causes piston 70 and member 74 to move upwardly by the action of spring relatching into assembly 88 which carries lower packing member 96. In this manner fluid above generator 30 is caused to go into the fluid existing below during the compressive through conduit 22 to actuate the apparatus where hy-' drostatic pressure is not available or is insufficient. A unidirectional (check type) valve can be located within outlet conduit 22 operable under predetermined pressure conditions in order to maintain sufficient back pressure within well space and cylinder 68 of generator 30 for operation. The implosive rarefaction pulse effect caused by the apparatus according to this invention places a momentary pressure differential between the well fluids and the fluids in the formation with the formation fluids tending to move towards the well. Thereafter, the rarefaction pulse effect is reversed by a high pressure impulse into the widened area of the formation near the well.

In another embodiment instead of a continuous lift swab an oscillating motion is transferred to wire line 18 from, for example, a cable tool drilling rig.

It can thus be seen that during what would be a normal swabbing of a well an implosive reaction occurs by proper setting of device 30 to the amount desired to formation 32.

PUMPING WELLS The apparatus of this invention has further utility when used in conjunction with a reciprocating type oil well pump. The implosive rarefaction pulse creates a momentary suction effect on the formation fluids bringing them into the pump proper for lifting to the surface. In addition, the high pressure positive pulse following causes debris, normally plugging the formation pores, to be forcefully radiated outward. The reciprocating movement of pump rods provides the necessary force to actuate generator 30 and to create the low pressure space with respect to the surrounding high pressure zones with further communication between them resulting in the implosive effect. This continued effect not only prevents clogging of the formation pores and fractures but is also sequence timed to assist fluid movement to the well surface. In one embodiment the implosive reaction pulse occurs during the upward pump stroke, however, this is not to be held limiting as the pulse can be initiated in the down stroke or on both strokes.

In reservoirs having substantial interstitial fluid pressures, the apparatus shown in FIGS. 3 and 4 may have its position inverted and be placed at a selected position in the Well bore adjacent the productive formation. When used in this manner, implosion wave generator 30 may be caused to operate in a periodic manner from the sustained pressure of the reservoir fluids. Regulation of the pumping of this formation pressure induced implosive reaction operated pumping means may be controlled at the surface as desired by the amount of fluid allowed to escape from the well head.

By proper location of this formation pressure operated implosive reaction pump from the bottom of the well bore as compared to the casing or tubing to the well head at the surface so that even multiples of a quarter ofa wave length or one of its harmonics may be allowed between wave generator 30 and the bottom of 16 the well bore and to the top of the well bore, then standing wave conditions may be set up in the well bore that will assist the pressure energy of the formation in pumping fluids therefrom, as well as in assisting in the continuing operation of device 30.

It is also possible to operate device 30 in the upright manner shown in FIGS. 3 and 4 as a pump actuated by sonic pulses or waves of any of the various types disclosed in my parental application Ser. No. 655,995, filed June 17, 1957, now US. Pat. No. 3,302,720, by placing apparatus 30 at a desired location in the well bore adjacent the productive formation wherein device 30 would be an assist in maintaining sonic wave energy in the well bore for pumping fluids from the formation.

WELL COMPLETION A typical completion or workover of subsurface formations using the implosive pulse generator of this invention is illustrated in FIGS. 10 and 11. Bullet or jet perforator 150 is fired from the surface or by timed sequence apparatus to provide openings 34 through casing 10 into formation 32. Communication exists thereafter, for example, from the formation to central bore 54 of mandrel 56 through the perforator 150.

Fracturing of the formation, if necessary or possible, occurs in many ways. For example, valve 40A is placed in an inoperative position by placing sufficient tesion on spring 44, shown in FIGS. 3 and 5, so that the valve will not open at low fluid pressures above this valve 40A. Generator 30 is actuated by pressure pulses in annulus fluid 15 from source 162 or which may be hydrostatic pressure. The implosive pulse plus the high pressure positive pulse reaches proportions sufficient to cause breakdown or rupture of the formation. In some instances incidental fracturing of the formation from the well bore occurs by the implosion effect. However, it is preferred to establish pressures in the space below generator 30 up to or near the formation breakdown pressure prior to initiating the implosive reaction pulse. Pressures sufficiently greater than the formation breakdown pressure are created to overcome the overburden pressure which is generally estimated as approximately equal in p.s.i. to the depth of the formation in feet.

As a further example of a fracturing procedure, valve 40A in housing 50 is adapted to open at a predetermined pressure. The setting of that pressure occurs through adjustment of coupling 12A being rotated with respect to threads 46 as described in FIGS. 3 and 5. In the preferred embodiment the valve is regulated and pre-set to open when the implosive rarefaction pulse is initiated in the coupling or fracturing fluid existing below packer 96 and in tubular bore 54. As the rarefaction pulse passes the lowermost portion of the mandrel an induced rarefaction wave is caused upward through the central bore creating a pressure differential across valve member 40A, opening same and inducing a pulse of pressure fracturing liquid from storage 154. The injection of such fluid in one embodiment is timed with the wave pulse directed toward the formation being treated to perform cancellation. reinforcement or augmentation of the induced wave pulses. The additional fluid or treating liquid in the wave pulse becomes useful as a makeup for fluids forced into the pores or fractures of the formation.

An even further procedure for rupturing or fracturing subsurface formations using apparatus of this invention includes use of rupture seal and valve 40A as illustrated in FIG. 5. When it is desired to use large 17 quantities of fracturing fluid after initiation of the fracture using implosive pulse generator 30, seal disc 130 is ruptured by pressure or go-devil 132. Pump or pumps 160 thereafter force additional fracturing fluid from storage 154 into the well to expand the fracture with or without simultaneous implosive pulses.

Although fracturing fluids have been particularly described above, this is not limiting as other well treating fluids such as acids, solvents, etc., stored in container 156 may also be used in the completion or workover of wells in conjunction with the implosive pulse generator 30.

As a further example of use of the apparatus particularly described in FIGS. and 11, after perforating and fracturing, a drill stern test of reservoir 32 can occur by rupture of seal disc 130 of valve 40A permitting fluids to enter tubing 11 for measurement. In the event productivity is insufficient for producing the formation, or water encountered, a still further embodiment includes pumping or squeezing of sealing materials such as cement into the formation using a pump 160 and sealing materials from storage, e.g., 158, in a manner well known to those skilled in the art. In some uses no more pressure is necessary than the hydrostatic head of cement within tubing 11 to effect operation.

Accordingly, it can be appreciated that this invention concerns apparatus which is capable of a multiplicity of separate well treating or completing operations assisted by implosive reaction pulses and the resultant energy therefrom. Typically, operation of generator 30 requires a separate power source 162 connected to the annular space and cylinder space 63. As heretofore explained, this may be a sonic generator, pump or compressor. In that instance where generator 162 is a sonic generator and is adapted to maintain a sonic standing wave to cause actuation of implosive pulse generator 30, it would be preferable to place the implosive pulse generator at a predetermined distance from the formation to be treated so that the distance therebetween can be acoustically coupled to a multiple of a quarter wave length of the sonic standing wave being created and/or maintained in the fluid above the implosive pulse generator 30 thereby causing reinforcement and augmentation of the implosion and their resultant reaction within the formation or at the face thereof by reflection.

The sonic generator 162 may impose on the produced sonic standing wave various modulations whereby the characteristics of the sonic standing wave actuating the implosive generator 30 may be extremely variable as to individual waves out of several composing the sonic standing waves. These periodic sonic waves actuating the implosive pulse generator 30 may be extremely variable as to individual waves in that they may have either variations of time and extent of the rarefaction or low pressure portion, or abruptness and shortness of time interval wherein vast pressure peaks may be imposed on the pressure portion, or at various phase angles of individual waves composing the periodic actuating sonic wave. Accordingly, implosive pulse generator 30 may have a predetermined setting given to its tripping means or member 116 in order that groups of the sonic waves from generator 162 that are substantially uniform or sinusoidal portion as to its rarefaction and compression portions thereof will cause the implosion device to be ineffective in operation and thus to serve merely as a transferring or transducing means for imposing sonic standing waves into the face of and within the interstices of the formation. When the modulations are imposed by the sonic generator 162 upon the periodic sonic standing wave actuating the implosive pulse generator 30, so that waves of large magnitude of non-uniformity or non-symmetry of rarefaction and compression portions occur as previously taught, then the implosive pulse generator will actuate to produce periodic implosion reactions on the sonic standing wave resonating at the face of and within the formation. Accordingly, the modulations produced by sonic generator 162 will be greatly enhanced, augmented, and amplified in being transferred through the implosive pulse generator 30. It is understood that the use of periodic sonic waves to actuate and enhance implosive pulse reactions as taught herein and in the above application and patents is applicable to the various methods taught in this application for uses of implosions including formation fracturing, fluid injection and producing methods as well as providing the pumping means for reservoir fluids of low vapor pressure with the lifting force being the type of modulations used on the pressure fluids maintained between the implosive pulse generator 30 and sonic generator 162.

When the various methods and means of my prior parental application Ser. No. 665,995 filed June 17, 1957, now US. Pat. No. 3,302,720, are used as the sonic generator 162 to operate bottom hole device 30, among several advantages as to the many uses listed in this application as to the combined use are the following:

It has been found during many years of use of various sonic wave methods and processes of treating subsurface formations that many productive formations have not sufficient interstitial fluid pressure and/or tightness of low enough permeability of the formation to sustain enough fluid pressure back onto a sonic wave generator operating at the surface so that enough intensity of sonic wave may be generated, unless relatively great amounts of fluids must be introduced through the sonic wave generator and into the well bore so that a highly pressured acoustic coupling may be maintained between the sonic wave generator and the formation.

Various pumping means have been attempted to be used in conjunction with the sonic wave generators in order to sustain high pressures upon the well heads, but it has been found that where the fluids were introduced apart from the sonic wave generator, the sonic waves had disruptive effects upon the pumping means and the pumping means often interfered with the desired output of the type of sonic wave from the sonic wave generator to the formation. In order to correct this, the fluids were introduced into the sonic wave at its point of generation in the sonic wave generator. Although this was extremely successful in operation in many formation treating methods and processes, the many variabilities of formations, even those in the same field or formation, varied the amount of fluid that was required to be pumped into the well bore in order to maintain a pressured fluid upon the sonic generator for it to generate the desired sonic wave intensity. This varying of the amount of fluid being introduced into the sonic wave at its moment of generation caused, where a piston type oscillator was the sonic wave generating means, an effective increase of lengthening of the stroke of the oscillator with an increase of input of fluid into the generated sonic wave. In order to be able to treat the extreme variability of formations found from well to well and from field to field, it was necessary to have the sonic wave ge nerator variably controllable as to its length of stroke, the accelerations available during said stroke, the control of amounts and pressures of inputing fluids into and through the sonic wave oscillator, and means to balance out the vibrations and pressures imposed upon the system by the sonic wave oscillators, among other things.

By use of device 30 in conjunction with my above described sonic wave generators, the control of the amounts of fluids desired to be introduced into a productive reservoir or formation can be selectively set prior to its introduction into a well bore by the adjustment of the compression of spring member 44 against valve means 40 or 40A as shown in FIGS. 3 and 5. By this means, device 30 may be moved from well to well in a particular field and a formation of substantially the same depth may be treated with about the same volume of fluid being introduced into each of the wells during a treatment of the same time period by a presetting of the opening pressure of valve means 40 or 40A. Thus, considerable of the variability of controls required in the operation of sonic wave generator 162 may be eliminated and device 30 may be a transference as well as a modulating and intensifying means for the various forms of sonic or energy carrying wave or waves from sonic wave generator 162.

In various treating and secondary recovery methods and processes wherein fluids in liquid form are imposed upon the deeper formations through well bores which often may be several miles in depth there is relatively enormous potential energy in the well bore adjacent the productive formation that may be effectively utilized by the combined use of the device 30 of this application and the methods and processes of my parental application Ser. No. 665,995 filed June 17, 1957, now US. Pat. No. 3,302,720.

This potential energy may be utilized by alternately applying or transforming its pressure force into an alternate implosive rarefaction and resultant reactive pressure shock' wave which may be, if desired, combined with various forms of sonic pulses or periodic waves by varying as desired the effective area of piston means 70 relative to that of the effective area of piston means or member 96, and the proper compression settings of spring compression means 80 and 98 as of FIG. 4 and applying to device 30 the controlling sonic pulse or waves from sonic generator 162 at the surface or well head. By proper matching of areas of piston means 70 and 96 relatively low pressures of formation fluids may be matched to high bottom hole pressures through device 30 and an acoustic coupling maintained therethrough so that a relatively high pressured small area of intense sonic wave may be transferred and transformed across into an effective larger area of sonic wave or waves that will be capable of allowing the gases contained in the fluids of the formation to come into and out of solution with the liquids so that effective treating of formations or driving of desired recoverable fluids from formations may be accomplished by being able to localize the sonic energy at the area upon which it is desired to be effectively used.

In regard to the last above, wherein it has been learned by considerable field experience that to effectively treat or drive fluids from formations that it is necessary to have a change of medium at the face of or in the formation at the areas in which the sonic wave energy is desired to be utilized. Where liquid is the acoustic coupling means between the sonic wave generating 20 means and the formation, it has been found best to use some form of gas as a receiving or localizing station or means. However, where the gas is liquefiable or is miscible or absorbable with the liquids of the formation at the pressures imposed thereon by treating or drive fluids, then in order to localize or cause reception of the sonic wave energy at the area desired it is necessary that the sonic wave energy have rarefactions of sufficient extent as by implosions or rarefied portions of the wave or waves, so that the gas may come out of solution and effectively release its work effect whether as in fracturing of formations or in pulling oil from interstices of formations. To exceed those pressures wherein gas may remain liquefied or always in solution allows sonic wave energy to travel past areas upon which it is desired to localize its energy and continues out into the formation until the sonic wave energy is attenuated at various receiving boundaries.

In undersaturated oil and gas containing formations wherein it is desired to utilize sonic wave energy in the various methods and processes taught in this application, it has been found that gas, preferably in a liquefied form, must be introduced to the area whereupon sonic wave energy is to be utilized. When this has been done by surface sonic wave generators as depicted by 162 of FIG. 11 of this application or of any of the sonic wave generators of my prior parental application Ser. No. 665,995, filed June 17, 1957, now US. Pat. No. 3,302,720, it has been found that gas being released from the formation comes back up the well bore, particularly so during treating operations such as fracturing, so that it collects at the well head and, unless it is continuously bled off, enough gas may accumulate so that interference with sonic wave transmission to the formation from sonic wave generator may result.

Also attempting to introduce gas in its liquefiable form or as a miscible or absorbable agent in the treating of drive fluids at the surface along with the generation of sonic wave energy causes considerable problems such as the proper pressures to hold on the well head relative to the adjusted formation pressure surrounding the well bore at the bottom of the bore. By the proper use of bottom hole device 30 along with surface sonic wave generators 162, gas may be introduced either intermittently or continuously as desired or dictated by formation conditions and the control of the amounts of gas and type thereof may be varied at will without interference with sonic wave transmission and control from the surface sonic wave generator 162. In such use of device 30 it would be preferable to replace upper swab cup 60 with a fixed packer to retain gas therebelow. By referring to FIG. 11 it may be seen that heat may also be introduced at or adjacent the formation, either in the form of heated vapors or liquids of various types and these introduced into the sonic waves during the rarefactions of the implosions or even of sonic waves transferred and transformed across device 30 and thus be compressed into the implosive reaction or the compression portions of the sonic waves going into the formation.

As a further embodiment of this invention wire line apparatus constructed according to that illustrated in FIGS. 13 and 14 is of particular utility in completing wells where smaller quantities of treating fluids such as acids, emulsions and corrosion inhibitors, etc., are adequate.

In operation, the treating fluids are placed in chamber 220 .above valved piston 238. This is ordinarily done at the surface with threaded member 200 and free piston 216 removed from the barrel 202. Barrel 202 is of sufficient length to provide the required volume of space 220 for treatment of the well; lengths up to several hundred feet or more for deep wells are taught.

In some instances valve piston 218 is removed, filling barrel 202 including chambers 220 and 226 with treating fluids above valve 40 in housing 50, which ordinarily attaches at lower threads 214. Usually the back-off safety joint 138 and implosive pulse generator 30 are below housing 50. Valved piston 218 or free piston 216 is placed on top of the treating fluid for isolation between batches of other treating fluids or well fluids acting through passage 206 and chamber 208 under hydrostatic pressure head. This latterpressure assists the entrance of treating fluid at predetermined phases of implosive reaction, usually the compression pulse through valve 40 into the producing formation.

If solid free piston 216 is used atop the treating fluids within chambers 220 and 226, treating fluid entry ceases when the piston strikes stop orifice 244. In many treating operations, however, it is necessary to follow one batch of treating fluid with a follower fluid. In that event valved piston 218 is placed atop the initial treating fluid with the follower treating fluid thereabove. In some instances one or more follower fluids are to be injected into the formation and this would necessitate additional valved piston members 218. Atop the last of these treating fluids solid free piston member 216 is used for isolation from the annular fluids- In operation with valve piston device 218, movement of the treating fluid into the formation occurs until piston 218 strikes stop orifice 244 as shown in the dotted line. Further pressure in the follower treating solution above forces the piston portion 238 from its seat 228 permitting fluid entry through orifices 242, 250 and/or 246 of the stop orifice. The follower treating fluid batches continue their injection until solid piston device 216 strikes valved piston 218. In some instances it is desirable to follow the treating fluids with fluid from well space 15. This is accomplished by utilizing valved piston device 218 as the top piston member.

In some well treating operations heating of the treatment fluids prior to their entrance to the formation is desired. Accordingly, a heating chamber 226 may be provided as shown attached to the lower portion of barrel 202. Electrical conduit 254 supplies electricity to a resistance type heating coil or coils 252 such as that sold under the trademark CALROD which has an errosive and corrosion protected and insulated cover. Although it has been found that the implosive pulse generator 30 in itself creates heat energy which is capable of being utilized in the formation, the heating chamber 226 adds additional heat energy into a desired phase angle portion of the compressive pulse resulting from the implosive reaction. This heating chamber 226 and coils 252 as described above may also be used above valve 40A where attachment means 12A of FIG. is used for connecting apparatus 30 to the surface in order to introduce therein fluids for treating formation 32. In this manner heated fluids are directly introduced into the compression or high pressure pulse that follows the rarefied pulse of the implosive reaction into the formation and upon attenuation of the pulses out of the formation this heat will be deposited therein for beneficial effects.

In addition to use as a wireline treating fluid injection chamber, the apparatus described in FIGS. 13 and 14 is 22 also capable of use with the implosive pulse generator 30 of this invention in combination with cement squeezing or plugging operations to seal off production of undesired fluids, patching leaks in casing, etc., at a minimum of trouble and expense.

SECONDARY RECOVERY It has been found that in many secondary recovery projects, e.g., water drive from an injection well to a producing well implosive reaction pulses can assist removal of oil trapped in minute pore spaces. Accordingly, the apparatus taught according to this invention has further application by placement within an injection well or alternately in both injection well and producing wells. In the latter instance, it is highly possible to cause cyclic pulsation through the formation by proper timing of the implosive pulse generators. For such use the producing well apparatus would provide means for lifting the fluids from the well to the surface.

It is entirely within the purview of this invention that in gas drive or underground combustion recovery techniques that implosive reaction pulses generated in accordance with this invention be utilized to assist gas flow or maintain combustion within the formation respectively.

Although I have described the apparatus of this invention as a removable type apparatus, i.e., using tubing or wireline, the apparatus is also capable of being permanently anchored or formed as a part of a permanent well completion apparatus capable of being placed into use at the demand of the operator. Accordingly, anchor slips may be formed as a part of the apparatus, as is well known tothose skilled in the art. In that event the upper packing member 60 is usually retained in a permanently sealed position. As heretofore described, a separate source of high pressure fluid is introduced into the generator 30 to cause operation.

In still another embodiment wherein valve 40 is allowed to operate, the device 30 may be anchored at a particular location and fluids pumped through the device and thus cause an alternating series of the implosive reactions, this being similar to the occurrence when device 30 is pulled upward against fluid in a Well, as in swabbing. That is, actuating fluids are pumped downward through annulus space 15 and thence through passageway 67 into cylinder space 68 against the top of sleeve or piston 74. This will cause an implosive reaction as previously described which in turn permits periodic release of the pressure fluid existing above valve 40. The periodic release of pressure fluid through valve 40 coincides with the frequency of the standing wave of the particular harmonic of the fundamental wave frequency in the fluid used below the generator unit 30. Additionally, the particular harmonic is created in accordance with the length of the unit 30 from the bottom of the well and the reflected quarter of a wave therefrom.

SEISMIC EXPLORATION ln seismic exploration and prospecting, a great many methods have been devised for furnishing the vibrational signal for reflection or refraction from or through geological formations deep within the earth in order to determine the depth and the degree and direction of slope of subsurface strata.

Among these methods the use of explosives has been the most popular. However, in the use of explosives for providing the energy for seismic profile signaling, there 23 has been considerable disadvantages in their use particularly as to marine seismic prospecting wherein destruction has been caused to marine life.

Many other methods have been devised to eliminate the use of explosives in marine seismic profiling, among them being the use of electrical sparks, gas exploders, etc., but the use of some of these methods does not provide enough vibrational energy to where the deeper subsurface strata is delineated or profiled as to its depths and contour.

By the proper use of implosions and the reactive implosive pulses seismic vibrational signals may be produced that will approach in strength those produced by explosives and these deeper strata may be profiled with less expense and destruction to the surroundings in which the seismic signaling is done as compared to the use of explosives.

In the use of implosion wave generator 30 of FIG. 4, outer casing may be towed behind a ship at a preselected depth in water and with device anchored at a fixed position in the casing, the pressure of the water upon device 30 producing implosions and resultant implosive reactions whose sonic or vibrational energy would penetrate the earth to which the sea water was acoustically coupled and the seismic signals reflected from or refracted through the various subsurface strata could be detected and recorded by geophones towed behind the boat at various locations, as in conventional marine seismic profiling.

If it was desired to provide a continuous implosive wave marine seismic profiler that could utilize certain proportions of the implosive pulses for assisting in creating other implosions, then device 30 could be located at a proper location within casing 10, which could be the center, and at certain towing speeds reflective pulses of a multiple of a quarter of a wave length or one of its harmonics of the two lengths of the pipe on either side of device 30 would set up standing wave conditions that would assist in continuing the implosive pulses within close tolerances as to periodic frequencies.

As an operating means, if desired, the forward end of casing 10 could be closed and have attached thereto liquid and sonic wave supplying means 162 and the actuation of the implosions could be sonic waves of any desired type and the implosions could be a modulating and intensifying means to the actuating sonic waves.

In location with enough water depth, casing 10 with device 30 therein could be vertically suspended from the ship or other buoyant member and actuation of the implosive reaction generator 30 could be by repeated lift ups and drops of the device within casing 10, or the operation could be by connection to sonic generator 162 as described above in relation to towing the casing and its device in a substantially horizontal plane.

The above described use of implosions in marine seismic profiling is not meant to limit the use of implosions to marine use, for implosions could be used for onshore use by various means, such as enclosing the bottom of casing 10 with a heavy plate which would acoustically couple to the earth and thus send vibrational energy waves into the earth for use in seismic profiling.

Such a use of acoustically coupling a heavy casing member 10 to the earth and sending seismic signals into the earth as of many of the various types of sonic or energy carrying waves that may be produced from the sonic wave generators as are disclosed in my parental application Ser. No. 665,995, filed June 17, 1957 now US. Pat. No. 3,302,720, of which this application has a continuation-in-part effect, was tested in the use of a small pilot model of the apparatus as shown in parent application Ser. No. 296,038 filed June 27, 1952, now US. Pat. No. 2,8665 09 before several individuals, among them being petroleum and reservoir engineers, wherein it was seen that with the casing member 10 being located some feet away from the sonic wave generating apparatus means, vibrational signals could be detected coming from the heavy casing member 10 for a considerable distance.

Further, it was found where sonic standing wave conditions of its fundamental wave length or one of its harmonics was imposed on the system and then a controlled modulation of one resonating sonic wave out of a great many resonating waves was caused to be intermittently applied to the system by the sonic wave generating apparatus, the resultant intense vibrational shock wave which could be clearly detected from the other sonic waves resonating through the earth could be received at a much further distance than could the main body of the sonic waves resonating through the earth. It was also determined that the greater seismic signaling effect was obtained where sonic wave energy was allowed to build up and accumulate in the system for a controlled period of time and then one wave had sonic wave energy and fluid withdrawn in a cavitational or implosive effect during the rarefaction portion of only the one wave cycle and the more substantially instantaneous and the greater the amount of cavitational or implosive effect the greater and more far reaching the resultant reactive shock wave vibrational seismic signaling.

Several months of experimentation was conducted with electronic timing instrumentation with the use of the above various types of modulated sonic and vibrational waves as to their velocity or time travel through various fluids wherein a particular recognizable type of modulated wave was timed at its creation moment in the sonic wave generating apparatus, timed as to its reflection time interval from the end of the casing 10 approximately 60 feet away through various types of fluids such as water, crude oil, various amounts of gases that were miscible or absorbable in the water or the oil, which gases could be caused to come in and out of the liquids during rarefactions of the resonating sonic waves and/or during rarefactions or cavitations of the one sonic wave being modulated out of the many sonic Waves resonating in the system.

Also tested, as above, was the time interval between the moment of creation of a particular type of modulated sonic or vibrational wave, as was recognizable by the phase angle at which it being modulated on the one sonic wave out of the many sonic waves whose energy was being accumulated in the system, and its reflection back through external lines containing various fluids including liquefiable gases of equal lengths with that which connected casing 10 with the sonic wave generating means 162.

Some of the findings of the considerable experimentation was that a certain type or form of intense modulated sonic or vibrational wave could be easily recognized from the other sonic or vibrational waves and timed as to amount of length that the modulated wave traveled through a particular type of fluid. It was found that water appeared to allow the greatest velocity of wave travel in the liquids tested and the slower velocity of wave travel through crude oil could be timed in its relationship to sonic wave travel through water. It was also found that where gases were introduced into the liquids, as by use of carbon dioxide with water or mixtures of methane and propane with crude oil, that proportionately as the increase of gas introduced in proportion to the amount of liquid used in the fluid system up to the saturation point of the gas into the liquid at the pressure maintained on the system above atmospheric pressure, then proportionately as to the velocity of sonic wave travel through the particular gas used and the amount of its relationship to the amount of the liquid used the velocity of sonic waves would be slowed down in its time travel by that proprotionate amount. Thus it was found that where a particular liquid was the acoustic coupling means from a sonic generating means 162 to the end of a casing or member and a peculiar or particular type of sonic or vibrational wave is created by modulating one wave from built up or accumulating sonic standing wave energy of a great many waves, then this one wave may be recorded at its moment of creation, go through the many wave lengths of the prime fundamental or one of its harmonics that is resonating under standing wave conditions between sonic wave generator 162 and the bottom end of casing 10, be reflected back through and on the standing waves to its source at 162 and be timed as to its travel from creation to reflection point and return.

Thus, by the above, as is well known, where the depth of the well bore of casing 10 is unknown it may be readily ascertained, where the velocity of sound in the particular liquid being used is known, by the recorded elapsed time between the time of creation of the modulated wave and its return.

When the large field model sonic wave generating apparatus as depicted in my co-pending application Ser. No. 406,045 filed Oct. 12, 1973 which is a continuing development of the small apparatus discussed as to its use in 1952, was placed into use in 1956 on waterflood injection wells and for fracture treating of productive formations considerable of the findings of experimentations of 1952 were substantiated in the field, as follows:

When the sonic generating apparatus 162 as of Ser. No. 406,045 filed Oct. 12, 1973 was placed upon an injection well and operated several hours with the use of sonic waves resonating in the well bore under standing wave conditions with the controllable modulation of one wave out of many sonic waves that were adding energy to the system, reflections of the modulated wave could be detected coming back onto sonic wave generator 162. With the continued use of sonic wave generator 162 with the modulation of the sonic wave being of a type created by heavy cavitational or implosive effects which by proper control were able to gather up by-passed by the waterflood oil and gas in the formation, then there would gradually begin a heavier reflection of the modulated wave from the formation until a level of detectable reflected wave energy would be obtained which would continue until shut down of the wave generator 162. It could be noted and detected that there were two reflections coming back to the well head, one a substantially uniform one that began after starting use of the modulated sonic waves in the well bore and another a later arriving in time reflected wave that increased to a heavy beat as the reflecting wall of gas and oil in the formation was built up. Thus recording means could not only record the distance to the bottom of the well bore but it could also delineate and give the underground distance to the progressing oil and gas front upon which the waterflood was pushing.

It was also found that the modulating sonic wave beats could be detected at some of the production wells, particularly those where water had broken through. Where a production well was gasing heavily the modulated sonic wave beat would be totally undetectable, showing that the gas in the interstices of the formation was reflecting or attenuating the sonic or vibrational wave energy. Those wells producing oil with very little free gas allowed a faintly detectable beat at the well head from the modulated sonic wave in the drive water to be recognized as coming through the banked up oil and gas front in the formation.

Later, in early 1957, when an oil producing well was being fractured and treated by the modulated sonic waves of the apparatus 162 as of Ser. No. 406,045 filed Oct. 12, 1973, and oil was used as the treating fluid, it was noticed that stronger beats were discernable and detectable at the well heads of offset oil producing wells then had been the case where the apparatus 162 was used on a water injection well and the change of sonic wave transmitting medium, as at the banked up oil and gas front, was between the well inputting the sonic waves and a well receiving seismic signals.

It could be seen from the above discussed results and observations that by acoustically coupling a sonic wave generator to a fluid containing formation, preferably liquid, that a change of medium or type of fluid could cause a change of signal strength in the different types of fluid mediums, or at a discontinuance thereof, so that geophones or like sensitive instruments for detecting and recording seismic signals could be used in contact with the earth at varying locations surrounding the well into which the sonic waves were being input and delineation or profiling of boundaries of fluids or fluid containing formations could be recorded and outlined as to their extent.

It was also obvious that the above methods and processes of outlining and profiling of various bodies or formations containing fluids as to the types or extent of the fluids as known by the seismic signal strength received and velocity or time travel between the recognizable seismic vibrational beats in different areas of the earth above the formation and/or between varying locations on the earth and the time at which the seismic signal was sent from the seismic signal source, all of which signals could be recorded on graphs for use as desired, could also be used to profile the subsurface contours of the fluid containing formations or surrounding formations or strata, by the seismic signals and/or the reflections or refractions therefrom received at varying locations on the earth or water above, as for instance by measurement of the distance between beats of the seismic signals received from a like seismic vibrational wave transmitting medium.

Thus it is possible to profile, delineate and outline substantially the extent of fluid containing reservoirs, the approximate boundaries of various types or mixtures of fluids contained in the reservoirs, as well as the subsurface contours of the fluid containing formations or the strata surrounding said fluid containing formations, with access being given to a fluid containing subsurface formation, preferably liquid, to which a seismic signaling means or apparatus may be acoustically coupled.

When the seismic vibrational wave signaling device is set at the surface as of 162 of FIG. 11, it may be any type or of sonic wave generator as described in detail in my co-pending application Ser. No. 406,045 filed Oct. 

1. A METHOD OF WELL COMPLETION OR WORKOVER OF OIL, GAS OR OTHER FLUID CONTAINING SUBSURFACE FORMATIONS INTO WHICH A WELL BORE HAS BEEN DRILLED, WHICH COMPRISES THE STEP OF PACKING OFF SAID FLUID CONTAINING SUBSURFACE FORMATION FROM SAID WELL BORE WHICH IS ABOVE SAID SUBSURFACE FORMATION WHILE PROVIDING CONTROLLABLE COMMUNICATION THROUGH TUBING BETWEEN SAID FLUID CONTAINING FORMATION AND A WELLHEAD AT THE SURFACE OF SAID WELL BORE, THEREAFTER CREATING SUBSTANTIALLY INSTANTANEOUSLY AT LEAST ONCE A LOW PRESSURE VOID OR ZONE OF RAREFACTION IN THAT PORTION OF THE WELL BORE WHICH IS IN COMMUNICATION WITH SAID FLUID CONTAINING SUBSURFACE FORMATION BUT BENEATH SAID CONTROLLED COMMUNICATION IN SAID TUBING, AND CREATING A NEGATIVE FLUID PULSE OR SURGE OF FLUID FROM SAID SUBSURFACE FORMATION INTO SAID CREATED LOW PRESSURE VOID OR ZONE OF RAREFACTION IN SAID PACKED OFF PORTION OF SAID WELL BORE THAT IS IN COMMUNICATION WITH SAID FLUID CONTAINING FORMATION.
 2. The method of claim 1 wherein said well bore has a casing or liner which is cemented through said fluid containing subsurface formation, comprising the additional step of packing off said cemented casing or liner above said fluid containing formation, providing communication between said lower packed off portion of said well bore and said fluid containing formation by perforating through said casing or liner.
 3. The method of claim 2 including testing the production of fluid from said subsurface formation through said tubing having controlled communication with said wellhead at the top of said well bore.
 4. The method of claim 3 inlcuding testing the production of fluid from said subsurface formation, and cementing or plugging through said tubing from said wellhead perforations producing undesired fluids.
 5. The method of claim 1 including following said negative pulse or surge of fluid from said subsurface formation into said packed off portion of said well bore by an injection of fluid into said fluid containing formation through said tubing having controlled communication with said wellhead at the top of said well bore.
 6. The method of claiM 5 wherein said injected fluid is inclusive of gases, solvents or emulsions.
 7. The method of claim 5 wherein said injected fluid is a gas or solvent.
 8. The method of claim 5 including thereafter testing production of fluid from said subsurface formation through said tubing having controlled communication with said wellhead at the top of said well bore.
 9. The method of claim 1 wherein said fluid containing formation is fractured by establishing formation fluid pressures up to or near the formation breakdown pressure in said packed off lower portion of said well bore which is in communication with said fluid containing formation prior to said creating of said negative pulse or low pressure void by the injecting of fluids at said wellhead through said tubing having controlled communication with said fluid containing formation.
 10. The method of claim 9 wherein said established formation fluid pressures have included therein gases.
 11. The method of claim 9 wherein said formation fluid pressures are created by pressurized gases, solvents or emulsions.
 12. The method of claim 9 including the further step of injecting additional fracturing fluids into said formation following said negative pulse or surge of fluid from said subsurface formation into said lower packed off portion of said well bore through said tubing from said wellhead.
 13. The method of claim 12 wherein said additionally injected fluid is inclusive of gases, solvents or emulsions.
 14. The method of claim 12 wherein said additionally injected fluid is a gas or solvent.
 15. The method of claim 12 including thereafter testing production of fluid from said subsurface formation through said tubing having said controlled communication with said wellhead at the top of said well bore.
 16. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said substrate formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, including following said negative pulse or surge of fluid from said subsurface formation into said packed off portion of said well bore by an injection of fluid into said fluid containing subsurface formation, wherein said injected fluid is inclusive of an acidizing agent or corrosion inhibitor.
 17. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said substrate formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, including following said negative pulse or surge of fluid from said subsurface formation into said packed off portion of said well bore by an injection of fluid into said fluid containing subsurface formation, wherein said injected fluid is heated prior to its injection.
 18. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been driLled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, including following said negative pulse or surge of fluid from said subsurface formation into said packed off portion of said well bore by an injection of fluid into said fluid containing subsurface formation, wherein said injected fluid is a formation cementing or plugging agent.
 19. A method of well completion or workover of oil, gas or other fluid containing subsurface formation into which is well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, wherein said fluid containing formation is fractured by establishing formation fluid pressure up to or near the formation breakdown pressure in said packed off lower portion of said well bore which is in communication with said fluid containing formation prior to said creating of said negative pulse or low pressure void, including the further step of injecting additional fracturing fluids into said formation following said negative pulse or surge of fluid from said subsurface formation into said lower packed off portion of said well bore, wherein said additional fracturing fluids are inclusive of an acidizing agent.
 20. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, wherein said fluid containing formation is fractured by establishing formation fluid pressure up to or near the formation breakdown pressure in said packed off lower portion of said well bore which is in communication with said fluid containing formation prior to said creating of said negative pulse or low pressure void, including the further step of injecting additional fracturing fluids into said formation following said negative pulse or surge of fluid from said subsurface formation into said lower packed off portion of said well bore, and thereafter testing production of fluid from said subsurface formation, and following said testing by cementing or plugging off undesired fluid production from said fluid containing formation.
 21. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid contaIning subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, including following said negative pulse or surge of fluid from said subsurface formation into said packed off portion of said well bore by an injection of fluid into said fluid containing subsurface formation, thereafter testing production of fluid from said subsurface formation, and following said testing by cementing or plugging off undesired fluid production from said fluid containing formation.
 22. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, wherein said low pressure void or zone of rarefaction is occasioned by a sonic wave generator, pump or compressor operated by a separate power source which imposes sonic waves or an increase of fluid pressure upon fluid contained in said well bore above said packed off lower portion of said well bore which is in communication with said fluid containing formation.
 23. The method of claim 22 wherein fluid contained in said well bore above said packed off portion thereof includes an acidizing agent and said operation by said separate power source allows the injection of said agent into said fluid containing formation following said creating of said negative pulse or surge of fluid from said subsurface formation.
 24. The method of claim 22 wherein fluid contained in said well bore above said packed off portion thereof includes or consists of gases or solvents and said operation by said separate power source allows the injection of said fluid into said fluid containing formation following said creation of said negative pulse or surge of fluid from said subsurface formation.
 25. The method of claim 22 wherein fluid contained in said well bore above said packed off portion thereof is a formation pressuring fluid and said operation by said separate power source allows the injection of said formation pressuring fluid into said subsurface formation following said creation of said negative pulse or surge of fluid from said formation.
 26. The method of claim 22 including thereafter testing production of fluid from said subsurface formation.
 27. The method of claim 22 including thereafter testing production of fluid from said subsurface formation, and following said testing by cementing or plugging off undesired fluid production from said fluid containing formation.
 28. The method of claim 22 wherein said fluid containing formation is fractured by establishing formation fluid pressures up to or near the formation breakdown pressure in said packed off lower portion of said well bore which is in communication with said fluid containing formation prior to said creating of said negative pulse or low pressure void.
 29. The method of claim 28 including the further step of injecting additional fracturing fluids into said formation following said negative pulse or surge of fluid fRom said subsurface formation into said lower packed off portion of said well bore.
 30. The method of claim 29 including thereafter testing production of fluid from said subsurface formation.
 31. The method of claim 29 including thereafter testing production of fluid from said subsurface formation, and following said testing by cementing or plugging off undesired fluid production from said fluid containing formation.
 32. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, wherein said creation of said low pressure void or zone of rarefaction becomes a source of seismic energy within said subsurface formation, and wherein said source of seismic energy following its creation is recorded at adjacent well bores to indicate the type of fluid or formation existing between said source of seismic energy and said adjacent well bores.
 33. The method of claim 32 wherein said low pressure void or zone of rarefaction is occasioned by a sonic wave generator, pump or compressor operated by a separate power source which imposes sonic waves or an increase of fluid pressure upon fluid contained in said well bore above said packed off lower portion of said well bore which is in communication with said fluid containing formation.
 34. The method of claim 32 wherein said low pressure void or zone of rarefaction comprises a substantially instantaneous rarefaction or cavitational modulation imposed on a sonic wave in said fluid in said lower packed off portion of said well bore which is in communication with said fluid containing formation.
 35. The method of claim 34 including varying the phase angle of said rarefaction or cavitational modulation in relation to said sonic wave, producing recognizable variations in said seismic energy recorded at said adjacent well bores.
 36. A method of well completion or workover of oil, gas or other fluid containing subsurface formations into which a well bore has been drilled, which comprises the step of packing off said fluid containing subsurface formation from said well bore which is above said subsurface formation, thereafter creating substantially instantaneously a low pressure void or zone of rarefaction in that portion of the well bore which is in communication with said fluid containing subsurface formation, and creating a negative fluid pulse or surge of fluid from said subsurface formation into said created low pressure void or zone of rarefaction in said packed off portion of said well bore that is in communication with said fluid containing formation, wherein said creation of said low pressure void or zone of rarefaction becomes a source of seismic energy within said subsurface formation, and wherein said source of seismic energy following its creation is recorded at the surface surrounding said well bore or at said well bore to indicate the type of fluid or formation existing in the subsurface formation.
 37. The method of claim 36, wherein said low pressure void or zone of rarefaction is occasioned by a sonic wave generator, pump or compressor operated by a separate power source which imposes sonic waves or an increase of fluid pressure upon fluid contained in said well bore above said packed off lower portion of said well bore which is in communication with said fluid containing formation.
 38. The method of claim 36 wherein said low pressure void or zone of rarefaction comprises a substantially instanaeous rarefraction or cavitational modulation imposed on a sonic wave in said fluid in said lower packed off portion of said well bore which is in communication with said fluid containing formation.
 39. The method of claim 38 including varying the phase angle of said rarefaction or cavitational modulation in relation to said sonic wave, producing recognizable variations in said seismic energy recorded at said surface or at said well bore. 